Paving stones or pavers are names which have been applied to concrete stones which are used in forming decorative patterns in walkways, patios, streets, and roadways. These stones are of nonrectilinear geometry, but rather commonly comprise "rounded" squares, oblongs, trapezoids, etc. Typical shapes of these products are depicted in FIG. 1 herein. In FIG. 2 there is depicted one architectural pattern of arranging such stones. As used herein, the term "stone" refers to a cast or compressed geometrical shape, normally of concrete or similar composition. The stone normally has at least one, and commonly two, flat surfaces, one bottom such surface being adapted to contact a supporting substructure such as a sand bed or other substructure, and the other top flat surface intended to face upwardly and, cooperatively with other stones, to form a flat surface over which foot or vehicular traffic passes. Typical stones may be "squares" of 3 to 6 inches across, or oblongs of 2 inches by 4 inches, all of which usually are of the same thickness, e.g. about 23/4 inches.
It has long been common in the building industry to employ rectangular concrete blocks in forming walls, etc. One apparatus for making such concrete blocks is shown in U.S. Pat. No. 3,671,165. Of recent, the apparatus as shown in such patent has been adapted to the manufacture of concrete stones of nonrectilinear geometry, specifically paving stones and the like. In U.S. Pat. No. 3,671,165 there is disclosed the technique of disposing "green", that is uncured, concrete blocks on a flat metal pallet for conveying to a kiln for curing of the block, such blocks remaining on the pallet during the curing process and further remaining on the pallets as the cured blocks are conveyed away from the kiln. It has been customary heretofore to convey the blockladen pallets to a cubing station, where a plurality of the blocks are arranged into individual tiers, the tiers being clamped at their sides with sufficient force to cause the rectilinear blocks to form a self-supporting unit that can be lifted as a unit off the pallet and then transported to a stack or cube comprising a multiplicity of tiers.
In the instance of paving stones which have nonrectilinear geometry, rounded edges, diverse geometries, etc. there is not know to be available any successful method or apparatus for clamping the stones arranged in a tier at their sides such that the tier can be successfully lifted off the pallet and moved to a cube without occasionally dropping one stone which causes the whole tier to fall. This is due in large part to the irregular geometry of the stones and their diverse geometries which prevents the development of proper horizontal pressure applied to the sides of the stones and conveyed through the tier from stone to stone that will permit the tier to be handled as a unit without a supporting pallet underneath the tier. Odd shaped stones commonly are removed by hand from the pallet and then placed in the cube. This is the general procedure for cubing rounds and triangulars since these shapes are especially difficult and often impossible to clamp into a self-supporting tier. Whereas some of the uniform shaped stones may be clamped to a degree sufficient to become self-supporting, even these stones frequently fall out of the clamped tier, such as when the mix is too wet and when the stones are cast and the sides of the stones slump creating bulging sides to the stones which are not amenable to clamping. The problem of dropping stones from a clamped tier is not limited to the loss of the stones themselves as through breakage or chipping, but rather, a serious problem associated with such drops is the loss in manufacturing time. Specifically, when a drop occurs, the entire manufacturing flow is shut down for that period of time required to clean up the broken and unbroken stones. In addition to the loss of manufacturing time, there is the accompanying extra cost of the manpower for performing the cleanup. These expenses of manufacture contribute to the ultimate selling price of the stone to consumers. A further problem exists in the instance of paving stones in that edge chipping during handling can not be tolerated because the stones are intended to be placed flat on a prepared surface to present an aesthetically pleasing pattern and such pattern is effectively destroyed by one or more stones in the pattern that have chipped edges.
Further, in the paving stone industry, it is becoming standard to place on the pallet entering the kiln a sufficient number of stones to constitute a tier of the intended cube of final product. Thus, as the pallet enters the kiln it contains a complete tier of stones. This tier of stones continues with the pallet through the kiln and is conveyed from the kiln to a cubing station, while still on the inital pallet. Other manufacturing practices involve production of the stones by any of several methods, accumulating the cured stones and thereafter arranging these stones in a tier on a pallet.
The present invention proposes a method and apparatus for accepting pallets of such paving stones or other similar stones and efficiently preparing the cube therefrom.
It is therefore an object of the present invention to provide a method for cubing paving stones or the like.
It is another object of the present invention to provide a method for cubing paving stones or the like wherein the stones in a tier are deposited substantially individually as a layer in a cube of such stones.
It is another object of the present invention to provide a method for cubing paving stones or like stones which minimizes the likelihood of breakage of the stones in the course of developing a cube thereof.
It is another object of the present invention to provide a method fur cubing paving stones or like stones which minimizes the likelihood of breakage of the stones in the course of developing a cube thereof.
It is another object of the present invention to provide a method for cubing paving stones or like stones which minimize the potential down-times of the stone manufacturing operations due to disruptions in the cubing operations thereof.
It is another object of the present invention to provide a method for cubing paving stones or like stones which can be essentially automated, thereby requiring a minimum of manual labor.
It is another object of the present invention to provide a method for cubing paving stones or like stones in which the stones are gripped along opposite sides thereof with a pressure which is less than that which is required to develop a self-supported unit of such stones and while so gripping the stones, arranging individual tiers thereof in a cube.
It is another object of the present invention to provide apparatus for cubing stones of nonrectilinear and/or diverse geometries.